1. Technical Field
The present invention relates to an inflator for an inflatable vehicle occupant protection device, such as an air bag.
2. Description of the Prior Art
An inflator for an inflatable vehicle occupant protection device, such as an air bag, includes a source of inflation fluid. The source of inflation fluid may be a stored quantity of pressurized inflation fluid, or a combination of pressurized inflation fluid and ignitable material for heating the inflation fluid. The ignitable material may be a solid material or may be a fuel gas, which is mixed in with the pressurized inflation fluid.
An inflator typically includes an initiator, which is actuated electrically when the air bag is to be inflated. Actuation of the initiator effects flow of inflation fluid from the inflator into the air bag to inflate the air bag. Certain of such inflators have an inflation fluid outlet with a flow area that varies in accordance with the pressure of inflation fluid in the housing.
The present invention is an inflator for inflating a vehicle occupant protection device. The inflator comprises a vessel containing stored gas and ignitable material. The vessel has a portion that provides a first opening for fluid to flow from the vessel when the pressure in the vessel reaches a predetermined pressure. The inflator also comprises an igniter for igniting the ignitable material and increasing the pressure in the vessel. The inflator also comprises a control part upstream of the portion for controlling fluid flow to the first opening. The control part defines a second opening that increases in size as the pressure in the vessel increases.